How to set an image as background image on a click?

Question

I have got an activity that shows a grid view with different images. When clicking on one of those images I want the clicked image to be the background image of another activity

Answer 1

Get the resource ID of the image you want as the BG and save it to preferences.

    public void onItemClick(AdapterView parent, View v, int position, long id) {
        saveImageId(position);
    }

private void saveImageId(int position) {
    int id = getImageId(); // get the R.drawable.* id of the image. You should be able to figure this out.
    Editor ed = PreferenceManager.getDefaultSharedPreferences(this).edit();
    ed.putInt("bg_image_id", id);
    ed.commit();
}

Now in your other activity, you can get the image id:

SharedPreferences prefs = PreferenceManager.getDefaultSharedPreferences(this);
int id = prefs.getInt("bg_image_id", R.drawable.default_background); //Get image id, use default background if there isn't one.
LinearLayout mLayout = (LinearLayout) findViewById(R.id.background_layout);
mLayout.setBackgroundResource(id);

Good luck